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Automated Fiber Placement A Buyer’s Perspective Looking At

The Future

Burak Uzman - ALA Group

Prof. Zafer Gurdal - TU of Delft

SME Manufacturing With Composites Conference 10/23/2012

Photo Courtesy of ElectroImpact

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Contents

Purpose and Scope

Definition of AFP In the context of this presentation

System Architecture

Heads and Tows

AFP vs Hand Layup - Cost Savings

AFP – Investment Decision

About Productivity and Rates

Productivity Analogy

Productivity and Laydown Rates

How To Increase C-Rate?

What is Next?

New Engineering Tools

ALDO and OLGA by ADOPTECH

Automation of Inspection

Conclusions

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Automated Fiber Placement (AFP)

Purpose of this presentation

To provide a new entrant buyer’s perspective

Economics of AFP

Process parameters that affect economics of AFP

Quantitative study of AFP productivity

Introduction to fiber steering and new design tools for AFP parts

Scope

Limit discussion to AFP machines that lay down slit tape.

No discussion on Automated Tape Layup (ATL), Pick and Place, and

dry fabric placement type systems.

No discussion of vendor specific AFP solutions or machine types.

ALA Group Proprietary Information

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AFP System Architecture

Ref: US Patent 8,151,854

Vertical Axis Gantry

Type AFP Machine Photo Courtesy of Ingersoll Machine Tool Inc

Horizontal AFP Machine Photo Courtesy of Ingersoll Machine Tool Inc

Robotic Arm AFP System

Photo Courtesy of Coriolis Composites

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AFP – Heads and Tows

Manufacturers Offer Three Types of Head Design;

Fixed Head

The head can’t be replaced in a production environment. The

spools are inside a creel house fixed to the machine.

Manually Replaceable Head

The head can be replaced by hand. Head replacement is not

automated.

Manually Replaceable Head

by Automated Dynamics

AFP Head

Spools

Tow

Path

Modular Head

The spools are on the head, and

the head replacement is automated

ElectroImpact Modular Head

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AFP – Heads and Tows

Tapes and Tows

Initial material form was towpreg.

Now almost everyone uses slit tape material that is made by slitting a wide

roll of uni directional tape into narrower strips.

Tow Width can be ½”, ¼” or 1/8”.

Tow Width is determined by

Part contour, head clearance

Minimum steering radius (e.g. laying up a spar)

Available machine type (½” vs ¼” machine)

Aircraft OEM’s cert. database

Number of Tow Lanes on a head are determined by;

Head clearance – how easily the head can get in and out

Manufacturer’s preference

Productivity and Reliability – Relationship between number of tows and

laydown rate can be counterintuitive.

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Merits of AFP – Cost Savings

AFP vs Hand Layup; $6 Million investment with 30 lbs/hr laydown rate.

Potential Cost Savings of AFP is around $16/lbs for solid laminates where price

metric is between $200/lbs to $310/lbs.

The catch: To recover the investment in 7 years, the manufacturer has to produce

around 35,000 lbs of composite laminates via AFP per year

Below 25,000 lbs/yr the investment has negative NPV.


~10 lbs/hr

Below a certain laydown rate AFP is

more expensive than hand layup per

pound of structure.

As the laydown rate goes down so

does the NPV

More on laydown rates later…….

Asymptote: y = Cost of Slit Tape

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The AFP Investment Decision

We Should Not Lose Sight of The Total Solution and Total Cost

Footprint Cost – Part of the Return on Assets (RoA) math for the corporate

finance dept. Some GMs are measured by revenue per square feet.

Foundation – some machines are heavier than others. Some require more

expensive foundations to achieve the same performance

Headstock/tailstock – some machines can eliminate the need for these

Tooling - Tool string can change drastically based on the type of machine bought.

Cost of additional heads for systems with changeable heads.

Installation costs

Software

Warranty

Cost of Spare components

Cost of Repair and Maintenance

Tech Support Cost


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Productivity - Analogy

One can think of an AFP System like a very expensive

office printer;

Paper jams, Printer Out of Paper, Ink Cartridge out of Ink…

Notice that the equipment never breaks down with a part

failure.

Process reliability versus machine reliability.

AFP process is similar, we run into similar issues;

Material outage, material reload, resin buildups, fuzz balls,

cutter breakage, miscut tows, twisted tows, tow

breakage…etc…etc

AFP System productivity is highly dependent on how quickly we

can resolve the issues between the spool and the head roller, as

much as it is dependent on the frequency of such events.

Ref:

http://www.freeimageslive.co.uk/free_stock_im

age/printer-problem-jpg

Ref: US Patent 7,353,853


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Productivity - Rates

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Laydown Rates


A-Rate (typical 120 lbs/hr)

Course Length

Off-Course

Movement

Linear

Speed/Acceleration

Number of Lanes (n)

B-Rate (typical 60 lbs/hr)

• MTTR

• Machine Design Features

• Failure Rate (λ)

• Number of Lanes

• Machine Design

• Material

C-Rate (typical 15 lbs/hr)

• Tool Load and Setup

• In-Process Inspection

• In-Process Fixes Tow Breakage

Tow Twist

Cutter Failure

Dropped Tow

Fuzz Balls

18 in 36 in 60 in 96 in 144 in

acc (g) acc (in/sec^2)

0.01 3.84 16% 22% 28% 36% 44%

0.05 19.2 35% 49% 62% 72% 80%

0.1 38.4 49% 66% 76% 84% 89%

0.2 76.8 66% 80% 87% 91% 94%

0.4 153.6 80% 89% 93% 95% 97%

Vmax = 1600 IPMCourse Length (in)

Vavg/Vmax

Hypothetical Laydown Rates for

Machines with Various Number of Tows

and Individual Lane Availabilities.

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Laydown Rate Limiters


C-Rate

B-Rate

A-Rate

Theoretical Max-Rate

Rate Loss Due to Finite

Course Length

Rate Loss Due to Off-

Course Movement

In-Process Inspection Time

Sample Part

AFP Machine

16 Tow Lanes

½” Tows

1600 IPM

Acc: 0.2g

Lane Availability: 97%

Inspection: 6.3 min/layer

Part

210 lbs

80 layers

1020 courses

Avg. Course: 59”

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How To Increase C-Rate and Profitability?

C-Rate determines the number of AFP Systems a manufacturer must

purchase to support rate production. Plus more….

A lower than expected C-Rate has major business implications for the

manufacturer;

Negative NPV for the investment and the production program.

Satisfying customer contract requirements most likely to require additional

capital investment (Cap-X)

Purchase of additional AFP Systems.

Purchase of additional cure fixtures/tools to be purchased.

Additional Floor space/facilities.

C-Rate is dominated by the time spent on inspection and fixes.

Develop an AFP System Qualification Process to reduce inspection


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What is Next?

Where AFP pays off;

Increase Productivity and Reduce Capital Investment

Place material with high accuracy in a repeatable/consistent fashion

Fabricate intricate parts – geodesic stiffened panels

Fabricate advanced structural configurations

What Is Next with AFP?



Cooperative tow placement

Automated 3D weaving/braiding


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New Engineering Tools Are Needed To Exploit

Individual Tow Manipulation and Steering

Capabilities of AFP.

Potential to reduce weight through the flexibility to

tailor the stiffness distribution of each ply.

Design (CAD) - How to document each tow’s 3D

shape? How do we check?

Analysis (FEA) - Can no longer assign MAT2 or

PCOMP to entire surfaces.

Producability - Tow buckling, wrinkling, shifting,

overlaps…

Engineering for Fiber Steering requires the Design,

Analysis and Producability Assessment Cycle to be

integrated.


Parallel Steering

Limited Tailoring,

Limited Weight

Reduction

Shifted Steering

Ply with tow drops

and tow adds

Significant tailoring

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Laminate Design Software by

ADOPTECH

ADOPTECH has developed a suite of composite design and analysis

optimization software modules.

Specifically suited for fiber-placed composite structures is a two step

optimization process utilizing ALDO and OLGA modules.

ALDO: Advanced Laminate Design Optimization

Structural weight optimization using FEM and other analysis tools.

Reduces complexity of design variables and number of analyses.

OLGA: Optimization of Laminates Using Genetic Algorithm

Optimizes stacking sequence, creates layup schedules and generates

blended laminate designs.

Incorporates manufacturing constraints and structural optimization

results.


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ALDO by ADOPTECH

Enables design optimization of different zones of the same part

Provides ideal stiffness distribution over the surface of the part.

Constant regions or variable stiffness solutions

Evaluates material failure, vibration, buckling aspects.

Gradient-based optimization provides fast convergence

Fiber orientation and stacking sequence no longer design parameters

Utilizes commercial FEM (NASTRAN) or customized analyses

Rectangular plate under shear buckling – 4 Design Zones

After 8 Iterations - Optimum

Thickness and Stiffness For

Each Design Zone


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OLGA by ADOPTECH

Genetic Algorithm for stacking sequence design

• Software converts the stiffness matrices to laminate stacking sequences

• Discrete variables not a hindrance

• Global search for optimal layup

• Customized ply configurations and laminate rules allowed

• Manages (Blends) stacking sequence transitions between design zones

• Includes manufacturing process constraints

“Blind Blending” solution minimizes number of unique ply/layer definitions

• Matches stiffnesses to optimal results from ALDO

• Includes production cost and time estimates from manufacturing packages


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In-process inspection time is significant!!! Directly affects floor to floor

rates, and profitability of the program

In-process inspection automation will likely to require technology

development in areas that are not core to the machine builders’

capabilities;

Machine Vision and Artificial Intelligence based software development

Markers/tracers in slit tape material

Multi spectral sensors development to sense multiple physical phenomena attributable

to composite materials

The Boeing Company already has a few patents in this area;

US7678214, US7807002, US6871684, US8158210, US7688434, US7555404,

US8184281, US7039485, US7171033, US7193696, US7236625….

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Increased Accuracies and Precision

For the advanced applications of AFP to become feasible, placement

and cut length tolerances need to be below 0.010”

Collaborative Tow Placement – Increasing Availability and Laydown

Rates

Multiple machines placing material on the same part at the same time.

Parallel system increases system availability, laydown rate linearly proportional to

number of lanes deployed.

Zone responsibility for each machine requires; precise splicing on long courses and

tight tolerances on tow-to-tow gaps/overlaps.

Automated Weaving/Braiding

Increase damage tolerance of the composite part by automated 3D weaving/braiding.

Can be done with splicing – requires significant improvement in cut length accuracy

Research with existing technology shows promising results.


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Conclusions

The technology has just overcome its “trough of disillusionment” in the

technology adoption hype cycle. Significant road ahead.

Functioning prototypes of the 90s are being replaced by first and second

generation products.

There will be new technologies, higher productivities, less expensive solutions,

new machines, new machine vendors. The business sure will change.

Gartner Group’s Hype Cycle For

Emerging Technologies


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